hw/arm/virt: Realize ARM_GICV2M sysbus device before accessing it

sysbus_mmio_map() should not be called on unrealized device.

Signed-off-by: Philippe Mathieu-Daudé <philmd@linaro.org>
Reviewed-by: Thomas Huth <thuth@redhat.com>
Message-Id: <20231018141151.87466-8-philmd@linaro.org>

hw/arm/virt.c

@@ -690,10 +690,10 @@ static void create_v2m(VirtMachineState *vms)
     DeviceState *dev;
 
     dev = qdev_new("arm-gicv2m");
-    sysbus_mmio_map(SYS_BUS_DEVICE(dev), 0, vms->memmap[VIRT_GIC_V2M].base);
     qdev_prop_set_uint32(dev, "base-spi", irq);
     qdev_prop_set_uint32(dev, "num-spi", NUM_GICV2M_SPIS);
     sysbus_realize_and_unref(SYS_BUS_DEVICE(dev), &error_fatal);
+    sysbus_mmio_map(SYS_BUS_DEVICE(dev), 0, vms->memmap[VIRT_GIC_V2M].base);
 
     for (i = 0; i < NUM_GICV2M_SPIS; i++) {
         sysbus_connect_irq(SYS_BUS_DEVICE(dev), i,